432 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



in this region. The Troplwnia affinis (Plate XIV, fig. 75) is more com- 

 mon, though found chiefly in the deeper waters, and more frequently in 

 the cold waters outside, as off Cuttyhunk Island and off Block Island. 

 Ampliarete setosa V. has been found only in Long Island Sound, near 

 New Haven. The Helinna cristata is a northern and European species ; 

 it was found in the deeper part of Vineyard Sound, inhabiting flexible 

 tubes covered with fine mud. Euchone elegans V. (Plate XVI, fig. 84) was 

 found in the deeper parts of Vineyard Sound, living in small tubes of 

 mud ; it was much more abundaut in the deeper waters outside. The 

 Meelcelia ingens (p. 349, Plate XIX, figs. 96, 96a) occasionally occurs on 

 muddy bottoms, though more common on sandy ones. 



Of Gastropod mollusks a comparatively small number of species oc- 

 cur that are characteristic of these bottoms. There are several species 

 that occur on eel-grass, when it grows on the muddy bottoms, which are 

 not included in the following list. They have been mentioned when 

 speaking of the fauna of muddy and sandy shores. 



Among the species of special interest were Mangilia cerina, which is 

 a rare and little-known species ; Bela plicata (p. 383, Plate XXI, fig. 

 107) ; Turbonilla elegcms, (p. 418, Plate XXIV, fig. 1'55), which was re- 

 cently described from specimens obtained in Vineyard Sound by us ; 

 T. interrupta, (p. 418 ;) two species of Scalaria, (p. 418 ;) Cylichna oryza, 

 (Plate XXV, fig. 164;) AmpMsphyra pellucida, (Plate XXV, fig. 162;) 

 and Utriculus canaliculatus, (Plate XXV, fig. 160). 



The bivalve shells are much more numerous and are mostly burrowing 

 kinds. Among the most abundant are Mulinia lateralis, (p. 373, Plate 

 XXVI, fig. 184 B,) which occurs in immense quantities, especially in soft 

 sticky mud ; GUdiopliora trilineata, (Plate XXVII, fig. 193 ;) Tellina tenia 

 (Plate XXX, fig. 225,) which is often very abundant in soft mud, in shel- 

 tered places, as in Hadley Harbor ; Gallista convexa, (Plate XXX, fig. 

 219 ;) Nucula proximo,, (Plate XXX, fig. 230 ;) Yolclia Umatilla, (Plate XXX, 

 232 ;) Astarte castanea, (Plate XXIX, fig. 204 ;) and Mytihis edulis, (p. 307.) 



The last-named shell, which is the common muscle, occurs in patches, 

 " beds," or " banks," often of great extent. One of these muscle-beds, in 

 which the animals were living, was found extending quite across the 

 mouth of Cuttyhunk Harbor, at line 75, /, on the chart ; another at 

 Quick's Hole, at line 76, c, and 45, a, b; others at 77, d, e,f; 46, b, c, d. 

 In several instances large beds of dead muscles were found, with few 

 living ones, and in all these cases there were on them large numbers of 

 star-fishes, either Asterias arenicola, in case of those in Vineyard Sound ; 

 or Asterias vulgaris on those in the deeper and colder waters near the 

 entrance of the Sound and off Gay Head j and sometimes both kinds, at 

 intermediate localities. These star-fishes had no doubt devoured the 

 muscles. Among the localities of this kind are, 47, a, b, c, d; 53, 6, c; 

 56, b, c, d ; 55, a, b, c ; 63, «, b ; 58, d ; 54, b. As this species of muscle 

 grows to full size, under favorable circumstances, in one year, it is prob- 

 able that these muscle-beds vary greatly in size and position in different 



